A1.2 - Nucleic Acids Flashcards
(29 cards)
What are the 4 major biological macromolecules?
Carbohydrates, lipids, proteins, and nucleic acids.
What are the 2 functions of nucleic acids in cells?
1) Pass information between generations. 2) Code for protein production.
What are the two types of nucleic acids found in cells?
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
What is the evidence for universal common ancestry based on nucleic acids?
All living organisms use DNA as their genetic material and use the same genetic code, which suggests a universal common ancestor.
Why are viruses not considered to be living organisms?
Because they are not made of cells, even though some use RNA as their genetic material.
What are the three components of a nucleotide?
1) A nitrogenous base (A, T, C, G, U), 2) A 5-carbon “pentose” sugar (ribose or deoxyribose), 3) A negatively charged phosphate group.
How are the three parts of a nucleotide connected?
By covalent bonds between the phosphate group, sugar, and nitrogenous base.
What are pentose sugars and how are they structured?
Pentose sugars have 5 carbon atoms (4 in the ring and 1 branching), and form a ring structure in the shape of a pentagon.
Which carbon in the pentose sugar does the nitrogenous base connect to?
Carbon 1 (C1).
Which carbon does the phosphate group connect to in RNA and DNA?
In RNA, to carbon 3 (C3); in DNA, to carbon 5 (C5).
What is the sugar-phosphate backbone in nucleic acids?
An alternating chain of phosphate-sugar-phosphate-sugar that provides structural stability to the nucleic acid polymer.
How are nucleotides joined during nucleic acid synthesis?
By a condensation reaction forming covalent bonds between the 5’ phosphate of one nucleotide and the 3’ carbon of the next, releasing water.
How many different nitrogenous bases are there and what are they?
Five: Adenine (A), Thymine (T), Cytosine (C), Guanine (G), and Uracil (U).
Which nitrogenous bases are purines and which are pyrimidines?
Purines (double ring): Adenine and Guanine. Pyrimidines (single ring): Thymine, Cytosine, Uracil.
What forms the genetic code in nucleic acids?
The sequence of nitrogenous bases in DNA or RNA.
What is a gene?
A specific sequence of nitrogenous bases in DNA that codes for the making of a protein.
How many nucleic acid bases code for one amino acid?
3 bases = 1 amino acid.
What is RNA and how is it structured?
RNA is a nucleic acid made of a single chain of nucleotides with bases A, U, C, and G. It has a sugar-phosphate backbone and runs from 5’ to 3’.
How is RNA synthesized?
Through a condensation reaction where the 5’ phosphate group of one nucleotide forms a covalent bond with the 3’ carbon of the next, producing water.
What is the structure of DNA?
DNA is a nucleic acid with two antiparallel strands of nucleotides joined by complementary base pairs and twisted into a double helix.
What are the complementary base pairing rules?
Adenine binds with Thymine (2 hydrogen bonds), Guanine binds with Cytosine (3 hydrogen bonds). In RNA, Adenine binds with Uracil.
What are the differences between DNA and RNA?
DNA: deoxyribose, 2 strands, uses Thymine, found in nucleus/mitochondria/chloroplasts, passes hereditary info.
RNA: ribose, 1 strand, uses Uracil, found in nucleus/cytoplasm/ribosomes, codes for proteins.
What are the similarities between DNA and RNA?
Both are nucleic acids, made of nucleotide polymers, have sugar-phosphate backbones, and share bases C, G, and A.
What is the role of complementary base pairing in DNA replication?
It ensures each strand serves as a template, so the resulting daughter strand has a complementary sequence that maintains genetic information.
